U.S. patent application number 16/298213 was filed with the patent office on 2019-07-04 for composite stretch yarn, process and fabric.
This patent application is currently assigned to SANKO TEKSTIL ISLETMELERI SAN. VE TIC. A.S.. The applicant listed for this patent is SANKO TEKSTIL ISLETMELERI SAN. VE TIC. A.S.. Invention is credited to Seref AGZIKARA, Esin KALFA KILICKAN, Kenan LOYAN, Mahmut OZDEMIR, Hamit YENICI, Mustafa ZEYREK.
Application Number | 20190203385 16/298213 |
Document ID | / |
Family ID | 44114274 |
Filed Date | 2019-07-04 |
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United States Patent
Application |
20190203385 |
Kind Code |
A1 |
AGZIKARA; Seref ; et
al. |
July 4, 2019 |
COMPOSITE STRETCH YARN, PROCESS AND FABRIC
Abstract
In a stretch yarn (1) comprising a stretchable core (2) covered
by an inelastic fibers sheath (3) the stretchable core (2)
comprises first and second fibers (4, 5) that have elastic
properties, the first fiber (4) is an elastomer and the second
fiber (5) is a polyester based (co)polymer, the amount of the
second fiber being in the range of 60-90% (w/w) of the total weight
of the fibers of the stretchable core (2); the first and second
fibers are connected together at least at a plurality of points
(P).
Inventors: |
AGZIKARA; Seref; (Inegol,
TR) ; ZEYREK; Mustafa; (Inegol, TR) ; YENICI;
Hamit; (Inegol, TR) ; OZDEMIR; Mahmut;
(Inegol, TR) ; LOYAN; Kenan; (Inegol, TR) ;
KALFA KILICKAN; Esin; (Inegol, TR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SANKO TEKSTIL ISLETMELERI SAN. VE TIC. A.S. |
Inegol |
|
TR |
|
|
Assignee: |
SANKO TEKSTIL ISLETMELERI SAN. VE
TIC. A.S.
Inegol
TR
|
Family ID: |
44114274 |
Appl. No.: |
16/298213 |
Filed: |
March 11, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13881534 |
Jun 4, 2013 |
10260175 |
|
|
PCT/EP2011/005723 |
Nov 14, 2011 |
|
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16298213 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D02G 3/328 20130101;
Y10T 428/2936 20150115; D02G 3/324 20130101; D02G 3/326 20130101;
D01H 5/70 20130101; D10B 2331/04 20130101; D02G 3/02 20130101; Y10T
428/249921 20150401 |
International
Class: |
D02G 3/32 20060101
D02G003/32; D02G 3/02 20060101 D02G003/02; D01H 5/70 20060101
D01H005/70 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 12, 2010 |
EP |
10014545.7 |
Claims
1. A single yarn comprising: a stretchable core; and an inelastic
fiber sheath covering said core, wherein the stretchable core
comprises first and second fibers each having elastic properties,
said first fiber is an elastomer and said second fiber is selected
from a polyester based (co)polymer and an elastomultiester, and
wherein the first and second fibers are twisted together and have
at least 300 twists per meter and said first fiber has an
elasticity and can be stretched of at least 400% and said second
fiber has an elasticity less than said first fiber, said second
fiber can be stretched of at least 20%.
2. The yarn according to claim 1, wherein the second fiber is in
the range of 60-90% (w/w) of the stretchable core.
3. The yarn according to claim 1, wherein the inelastic fiber
sheath completely covers said core and the stretchable core is
drafted from 1.12 to 1.16 times its original length.
4. The yarn according to claim 1, wherein said second fiber is an
elastomultiester bicomponent fiber and said first fiber is a
polyolefin or a polyurethane elastomer.
5. The yarn according to claim 1, wherein said first fiber and
second fiber are bound together so as to be stretch and to recover
together as a single fiber.
6. The yarn according to claim 1, having an NE count within the
range of 5 to 40, wherein the amount of core fibers is from 25 to
35% (w/w) of the total weight of the yarn and wherein the amount of
the second fiber in the core composite fiber, is within the range
of 75% to 87% by weight and the inelastic fiber sheath completely
covers said core.
7. The yarn according to claim 1, wherein said sheath fibers are
cotton fibers, said first fiber is elastane and said second fiber
is a PTT/PET bicomponent fiber.
8. A stretch fabric including the yarn according to claim 1.
9. A garment that contains the stretch fabric according to claim
8.
10. An apparatus for producing a stretch yam according to claim 1,
comprising: a frame for attaching a source of roving (8) and a
source of a composite stretch core fibers (2), draft means for
stretching said core fibers (2) with a draft ratio of the composite
core (2) within the range of 1.05 to 1.16, and means for spinning
said roving (8) around said core (2) to completely cover said core
(2) with a sheath (3).
11. An apparatus according to claim 13, further comprising
pre-tensioning means (10) for said stretch core (2).
12. An apparatus according to claim 13, further comprising guide
means (15,16) for tensioning said roving (8).
13. An apparatus according to claim 13, wherein said tensioning
means for the said stretch core (2) comprise draft rollers (14) and
a couple of rollers (11) supporting a rolling weight (12).
14. A stretch core (2) yarn, comprising first and second fibers (4,
5) that have elastic properties, said first fiber (4) is an
elastomer and said second fiber (5) is a polyester based
(co)polymer, said second fiber being in the range of 60-90% (w/w)
of the stretchable core (2), and wherein said first and second
fiber are connected together at least at a plurality of points.
15. A stretch core yarn (2) according to claim 14, wherein said
first and second fibers are coextruded or intermingled or
twisted.
16. A stretch core yarn according to claim 14, wherein said first
fiber is a polyurethane or a polyolefin elastomer, such as
elastane, and said second fiber is a PTT/PET bicomponent fiber.
17. The yarn according to claim 1, wherein the second fiber has a
smaller elasticity than the first fiber.
18. The yarn according to claim 1, wherein the second fiber has a
higher recovery amount than the first fiber.
19. The yarn according to claim 1, wherein the twisted together
first and the second fibers have 300 to 600 twists per meter.
20. The yarn according to claim 7, wherein the NE count is within
the range of 6 to 30.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of U.S. application Ser.
No. 13/881,534 filed Jun. 4, 2013, which is a National Stage of
International Application No. PCT/EP2011/005723 filed Nov. 14,
2011, claiming priority based on European Patent Application No. 10
014 545.7 filed Nov. 12, 2010, the contents of all of which are
incorporated herein by reference in their entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to a composite stretch yarn
and the stretch woven fabric comprising such yarn. The invention
also relates to an apparatus and a method of producing said stretch
yarn.
BACKGROUND OF THE INVENTION
[0003] More specifically, this invention relates to a stretch yarn
having a composite core and a cotton fibres sheath; a preferred
stretch fabric is denim.
[0004] There are several ways to make stretch fabrics in woven
textile industry; mono stretch fabrics include elastic yarns only
in warp or weft direction, in bi-stretch fabrics both in warp and
weft directions elastic yarns are used.
[0005] The most common way of producing stretch fabric is weft
(filling) stretch fabrics. Weft stretch fabrics have non elastic
warp yarns and elastic weft yarns. In these fabrics different kind
of elastic weft yarns such as corespun elasthane yarns, twisted
elasthane yarns, intermingled or twisted synthetic elasthane yarns
etc. are used. Elastic yarns are well known; the earlier fabrics,
such as in U.S. Pat. No. 3,730,679 comprised stretch yarns that
contained one elastomeric fiber and cotton fibers. These yarns
provided fabrics with low recover after stretching: a typical
elongation of these fabrics is of 15 to 40% in the weft direction,
but the recovery characteristics are very low, usually as low as
about 90% (ASTM D3107), i.e. the fabric has a growth of about
10%.
[0006] To solve this problem, woven stretch fabrics comprising
polyester bicomponent fibers have been disclosed, for example in
U.S. Pat. Nos. 5,922,433 and 6,782,923. The fabrics disclosed in
these references are comprised of bare bicomponent fibers and have
strong synthetic appearance and hand due to the exposure of the
bicomponent fibers on the fabric surface.
[0007] There is another way to make stretch fabric without using
elasthane, in this type of fabrics usually elastic type of
synthetic yarns are used like PBT, PTT or T400, i.e. a bicomponent
PTT/PET.
[0008] Stretch denim fabrics made from a bi-component polyester and
cotton are described in U.S. Pat. Nos. 7,310,932 and 5,874,372.
However, fabrics made from elastic polyester lack good
elasticity.
[0009] US 20080268734 discloses an elastic composite yarn
comprising a core bi-component fiber in a cotton fibers sheath; the
core comprises an elastic fiber and an inelastic fiber loosely
wound around the elastic one. The purpose of the inelastic fiber is
to improve the recovery properties of the yarn, so as to increase
the recovery properties of the fabric including the above mentioned
yarns. Drawbacks of this embodiment are that the inelastic fiber of
the core is also acting as a block to the stretch of the elastic
fiber and that the bundle of inelastic fibers appears through the
cotton sheath in the final fabric.
[0010] The surfacing of the elastic core in the inelastic fibers
sheath also occurs in other types of stretch yarns.
[0011] Therefore, there is the need to improve the known techniques
and to provide a stretch yarn that can provide stretch fabrics with
reduced fabric growth and still having a good stretch
performance.
SUMMARY OF THE INVENTION
[0012] It is an aim of the present invention to solve the above
problems and provide yarns and fabrics having great elasticity and
excellent stretch recovery.
[0013] A further aim is to provide a stretch yarn that is
completely covered by the fibres sheath, preferably a cotton fibres
sheath, without the core surfacing through the fibres, especially
after use.
[0014] Such an aim is obtained by means of the yarn according to
claim 1. According to the invention the yarn has a stretch core
comprising at least two fibers, or bundle of fibers, having elastic
properties and wherein at least one has excellent recovery
properties.
[0015] A further object of the invention is a fabric, particularly
a denim fabric, containing a stretch yarn as above defined.
[0016] The invention also relates to a method of producing a
stretch yarn according to claim 9, said method comprising:
providing a stretchable core comprised of first and second fibers
that have elastic properties, said fibers being connected together
in at least a plurality of points; wherein said first fiber is an
elastomer and said second fiber is a polyester based (co)polymer,
said second fiber being in the range of 60-90% (w/w) of the
stretchable core; tensioning said fibers and providing a sheath of
inelastic fibers to completely cover said core.
[0017] With the wording "first fiber" or "second fiber" of the core
it is meant a bundle of fibers, such as in elasthane and in T400
elastic fibers; with the wording elastic properties it is meant
that in the fibers some elasticity is always present and that in
some preferred embodiments further elasticity can be developed with
a thermal treatment.
[0018] Another object of the invention is an apparatus for
producing a yarn as defined according to claim 13.
[0019] This apparatus comprises means for housing at least a cotton
roving and a composite core bobbin for each spool and spindle, and
further comprises tensioning rollers to draft the composite core
yarn before feeding it together with the cotton staple fibers to a
spindle or equivalent device.
[0020] Further objects of the invention are a fabric including the
invention yarn and a garment that contains the above mentioned
fabric. Another object of the invention is a stretch yarn according
to claim 17.
[0021] According to an aspect of the invention, the second fiber is
a bi-component polyester fiber, preferably a PTT/PET fiber.
[0022] The two fibers, or bundles of filaments, must be connected,
i.e. bound, together to provide a final elastic "core yarn" that
combines the technical characteristics of the two, or more, bundles
of filaments. More particularly, the first fiber, that is an
elastomer, has very good elastic and stretch properties, while the
second fiber is a polyester based fiber having excellent recovery
properties.
[0023] In general, the first elastic fiber can be stretched at
least 400% and the second fiber is less elastic but can be
stretched at least 20%; an important property of the second fiber
is its recovery property, at least 90%, preferably 93%, most
preferably at least 96% or 97% or higher of the fiber.
[0024] Concerning the connection of the two fibers, this should be
carried out at least at a plurality of points.
[0025] According to a preferred aspect of the invention, the first
and second fibers are connected together by intermingling or
co-extrusion or by twisting. Especially when the second fiber, too,
is made of two different polymers, e.g. it is an elastomultiester
such as PTT/PET and similar filaments, such as those disclosed in
EP 1846602, coextrusion of the three polymers appears to be an
advantageous production process.
[0026] Intermingling is carried out according to the known
techniques of the art, such as open or closed intermingling jets.
The system is arranged to provide a number of connecting points
that is within the range of 50 to 200 points per meter, preferably
80 to 120 points per meter and most preferably 95 to 105. The
method of measuring the number of intermingling point is by direct
count of the combined fibers; in the latter method, the elastic
core "yarn" is put on a black or dark surface and is inspected by
eye, possibly with a magnifying glass, and the connecting points in
a meter of yarn are manually counted.
[0027] As recited in claim 1, in an exemplary embodiment the core
fibers of the invention yarn are connected to each other by
twisting. This means that twisting is not carried out loosely (i.e.
with about 75-125 twist per meter, as in above quoted prior art
US'734) but that the number of twists per meter is sufficiently
high to provide a connection between the fibers.
[0028] For twisting of a bicomponent fiber and elasthane a
preferred range is 300-600 twist/meter, preferably 350-550, in
general at least 400 and most preferably 450-525 twist per
meter.
[0029] In a preferred embodiment, before connecting the first and
the second core fibers at least the first, elastic, fiber is
stretched, so that after interconnection the released fiber will
recover and reduce its length. This will result in an amount, or in
a length, of the second fiber being available for stretching of the
the core, multicomponent, yarn; the composite yarn can be
significantly stretched even if one of the two fibers (so called
second fiber) is less or much less elastic than the other, first,
fiber. Preferably, the first elastic fiber is stretched with a
draft ratio of 2.5 to 4.2, more preferably 3.0 to 4.0 times and
most preferably about 3.5. It should be noticed that in the
exemplary embodiment the interconnected first and second fibers of
the core of the invention yarn act substantially as a single fiber,
contrary to what happens in prior art embodiments. The high
recovery properties of the second fiber will result in the
invention yarn, and, more particularly, in the final fabric, being
at the same time stretchable and with excellent recovery. Preferred
interconnection is by fibers intermingling.
[0030] The non elastic sheath or cover is made of non elastic
fibers, namely staple fibres and preferably the fibers are cotton
fibers.
[0031] The amount of the second fiber in the composite elastic core
of the yarn, i.e. the sum of all elastic fibers, is 60% to 90% by
weight, preferably 73% to 87% by weight on the total weight of the
core fibers.
[0032] According to the invention, the composite elastic core is
stretched before being spun with the staple fibers, the draft ratio
of the composite core is within the range of 1.05 to 1.16 and
preferably from 1.12 to 1.14. The draft or stretch ratio is
generated by the difference of the speed of the rollers that feed
the composite core fibers to the spinning device and is calculated
as the ratio of the speed of the faster roller and the speed of
slower roller (faster/slower); the speed is that of a point on the
cylindrical surface of the roller. When the composite core is
drafted in the preferred range of 1.12 to 1.14 the resulting yarn
is totally free from surfacing of the core through the staple
fibers and the yarn can provide a final fabric having an even color
effect and a hand that cannot be distinguished from a corresponding
fabric free from stretchable yarns.
[0033] The amount of elastic core (elastic fiber and polyester
based fiber (mono or bi-component) in the yarn is depending on the
English cotton count (NE) of the yarn and depending on the title,
e.g. the deniers, of the core fibres; in a preferred embodiment,
the yarn NE count is within the range of 5 to 25 and the amount of
core fibers is from 8 to 35% (w/w) on the total weight of the yarn,
preferably 8 to 30%. Possible combinations of the two fibers are,
in the case of Huvis, or T400, and elasthane (Lycra), the following
ones (in deniers) 70/40; 70/70; 50/40; 50/20; 30/40; 30/20; 70/20;
50/70; 30/70, the first value refers to the denier of Huvis or T400
and the second one to denier of elasthane. The range of the amount
of core fibres can be as low as 3.5-23.6% (w/w) in the case of the
combination 30/20, where the NE is in the range 6-40 and the draft
ratio is 1.14. A combination 70/70 will provide useful yarns with a
draft ratio of 1.14, NE of 6-20 and an amount of core fibers within
the range of 8.9 to 29.7.
BRIEF DESCRIPTION OF THE FIGURES
[0034] The invention will now be further disclosed in greater
detail with reference to the drawings enclosed for non-limiting
purposes, in which:
[0035] FIG. 1a and FIG. 1b are a schematic view of a stretch yarn
according to the invention;
[0036] FIG. 2 is a schematic front view of an apparatus suitable
for the production of a composite core stretch fiber;
[0037] FIG. 3 is a side view of an apparatus for the production of
the stretch yarn of the invention.
DESCRIPTION OF AN EXEMPLARY EMBODIMENT
[0038] In the present description, the term "w/w" means (as is
known in the art) weight on weight, e.g. as in the amount in weight
of first fiber with respect to the total weight of the core fibers
of the invention yarn. The word "(co)polymer" means "polymer or
copolymer".
[0039] With reference first to FIG. 1a and FIG. 1b, the stretch
yarn 1 of the invention comprises a stretchable core 2 and an
inelastic fibers sheath 3 that covers core 1; the stretchable core
1 comprises first and second fibers 4, 5, more precisely bundles of
filaments, that have elastic properties, more particularly, first
fiber 4 is an elastomer known in the art and second fiber 5 is a
polyester based (co)polymer, known in the art. First and second
fibers are connected to each other or secured together at least at
a plurality of points P. Preferably, one of the fibers is more
elastic than the other and the other fiber has greater recovery
than the first one.
[0040] FIG. 1a refers to an embodiment in which the fibers are
coextruded and FIG. 1b to an embodiment in which the fibers are
intermingled; the co-extruded fibers are connected substantially
continuously and the intermingled fibers at connected at a
plurality of points P.
[0041] Suitable materials for the first fiber 4 are polyurethanic
fibers such as elasthane, spandex and those fibers that have
similar elastic properties and in general fibers that can stretch
at least for 400% of their initial length (e.g. as elongation at
break). Further examples of elastomeric fibers used in the
invention include but are not limited to, Dowxla, Dorlastan (Bayer,
Germany), Lycra (Dupont, USA), Clerrspan (Globe Mfg. Co., USA),
Glospan (Globe Mfg. Co., USA), Spandaven (Gomelast C.A, Venezuela),
Rocia (Asahi Chemical Ind., Japan), Fujibo Spandex (Fuji Spinning,
Japan), Kanebo LooBell 15 (Kanebo Ltd., Japan), Spantel (Kuraray,
Japan), Mobilon (Nisshinbo Industries), Opelon (Toray-DuPont Co.
Ltd.), Espa (Toyoba Co.), Acelan (Teakwang Industries), Texlon
(Tongkook Synthetic), Toplon (Hyosung), Yantai (Yantai Spandex),
Linel, Linetex (Fillatice SpA). More generally, these fibers have
very good elastic properties and are highly stretchable. Polyolefin
fibers could also be used.
[0042] The second fiber 5 is a fiber with limited elasticity level
(less than the first fiber but at least 20%) but high recovery
properties (more than the first one); as previously mentioned, said
second fiber amount with respect to the total core combination of
fibers, is in the range of 60-90% (w/w) of the weight of
stretchable core fibers.
[0043] Suitable materials are polyesters and elastomultiesters such
as PBT and the bicomponent polyesters PTT/PET and similar disclosed
e.g. in EP 1846602.
[0044] Preferably, as shown in FIGS. 1a and 1b, second fiber 5 is a
PTT/PET bicomponent elastomultiester, such as the products
commercially available from Huvis e.g. as Zentra, or as T400 from
Invista.
[0045] Suitable fibers for the sheath 3 are fibers such as cotton,
wool, polyester, rayon nylon and similar, preferably cotton staple
fibers, to provide a natural look and a natural hand to the elastic
yarn; as previously mentioned, the sheath 3 is provided in such a
way as to completely cover the stretch core 2. To this end, any
suitable process is used to cover the core 2 with the cotton fibers
3; a preferred process is ring spinning.
[0046] The amount of cotton in the final yarn (core+sheath)
typically is within the range of 60-95%, preferably 70-92% (w/w),
according to the deniers of the core 2. The amount of twist per
inch is also depending on the features of the yarn; generally, for
the yarns according to the present invention, in the formula
T/inch=.alpha. NE, where T/inch is the number of twist per inch,
.alpha. is the twist multiple and NE is the English cotton count;
the value of .alpha. is within the range of 4.0 to 5.0, preferably
of 4.4 to 4.6, most preferably 4.5.
[0047] As will be better explained hereinafter, the multicomponent
core 2 is stretched with a draft ratio of at least 1.05, preferably
of at least 1.1 and most preferably of 1.14 prior to being spun
with the fibres to provide sheath 3. The tensioning step results in
a perfect centering of the core in the sheath and in the
possibility of having better cotton coverage of core "yarn" in the
final yarn (core+cotton cover/sheath); the yarn thus obtained as
well as the fabrics produced with said yarn, have a look and a feel
that cannot be distinguished from a yarn or a fabric not provided
with the stretch core while at the same time being provided with
excellent elastic and recovery properties.
[0048] Tests carried out on fabrics made with the stretch yarns
according to the invention and corresponding fabrics made with
stretch yarns comprising only elasthane as core fiber show that the
recovery of the invention fabric is at least 50% higher than the
recovery of the control fabric. Recovery improvement can be up to
100%.
[0049] It is believed that this excellent result is due to the
combination of three elements together to achieve the best
performance. The invention combined a fiber (possibly composite)
with very high recovery performance elastic yarn but with weak
elasticity level (such as Zentra or T400--PET/PTT) together with an
elastic fibre, such as elasthane (lycra, dorlastan etc.), with
great elasticity levels.
[0050] The two fibers are attached together with intermingling,
twisting or co-extrusion technology and this combined core yarn has
been put inside of the cotton sheath. In this way a yarn that has
the best elasticity, the best recovery and with excellent cotton
touch was obtained.
[0051] Twisting can be carried out in a way known in the art, such
as e.g. by Ring twisting or Hamel or 2for1; intermingling is
carried out, according to the known art or according to the
following method.
[0052] A T-400 yarn package is loaded on the creel (not shown). The
T-400 yam is guided to a feeding roller and wound around the roller
five times. An elastomer, e.g. Elastane yam package is loaded on
draft rollers to be provided a draft, and the Elastane yarn is
guided through a sensor and combined with T-400 yam at a feeding
roller. From the feeding roller the combined fibers are guided to
an Intermingling Air Jet 18, e.g. a Sincro Jet intermingling device
from Fadis, Italy.
[0053] Subsequently, the intermingled fibers are guided to a
lubricating station and are eventually wound on composite yarn
package 6 that is shown in FIGS. 2 and 3 after having being mounted
in the invention apparatus. The system is arranged to provide a
number of connecting points that is within the range of 50 to 200
points per meter, preferably 80 to 120 points per meter and most
preferably 95 to 105.
[0054] FIGS. 2 and 3 show a preferred embodiment for the production
of a yarn according to the invention.
[0055] In a typical composite core 2 as above disclosed, comprised
of T400 and elasthane, the T400 fibers have 75 Denier and elasthane
fibers have 40 or 70 Denier. The yarn count of this composite core
is 81.5 or 90 denier which is 2.25-7 times thicker than regular
corespun elasthane yarns.
[0056] Due to the dimensions of a T400+Elasthane composite core 2,
the relevant bobbin is much bigger than a bobbin of elasthane;
therefore, as shown in FIGS. 2 and 3, bobbin 6 of core 2 is located
on a frame 9 close to cotton roving spool 7.
[0057] T400+Elasthane composite core "yarn" 2 is guided between two
tension bars 10 that are used to give a low pre-tension to the
yarn, just to align and straighten yarn 2. This is very useful in
view of the nature of composite core "yarn" 2, especially when the
composite yarn is obtained by intermingling of two fibers, namely
T400 and elasthane. From pre-tension bars 10, composite core 2 is
fed to two driving rollers 11 on which a weight 12 is placed; core
2 is guided between the driving rollers and the weight 12 to avoid
free movement of the core yarn with respect to the rollers 11,
however, other suitable means for imparting a controlled speed to
the core yarn 2 may be used instead of the combination of rollers
11 and weight 12, e.g. means such as draft rollers known in the
art.
[0058] The advantage of the above disclosed arrangement is mainly
in the fact that the same apparatus can be used also to prepare a
standard elasthane core yarn: in this case the elastane fibre is
loaded in a package that is placed on the rollers 11 in the place
of weight 12.
[0059] From the first drafting arrangement 11, 12, core yarn 2 is
guided to a rolling guide 13 and from it to draft rollers 14, that
are the foremost couple of a plurality of drafting rollers for the
cotton roving 8, known per se in the art. Cotton roving 8 is guided
from spool 7 in front of pre-tension rollers 10, tension rollers
11, into a first guide 15 and a second guide 16; as can be seen in
FIG. 3, guide 15 is staggered to the front of the apparatus with
respect to second guide 16 in order to create a tension in the
roving and keep the roving in a fixed position, avoiding that the
roving moves freely.
[0060] From guide 16, cotton roving 8 is sent to draft rollers 17,
18 and 14. Draft rollers 14 are in common between core yarn 2 and
roving 8.
[0061] According to the invention, core yarn 2 is tensioned before
being coupled with the cotton roving, the tensioning or stretching
is obtained by means of the speed difference between rollers 11 and
rollers 14, i.e. the speed difference between rollers 11 and the
last draft roller 14 create the draft ratio in composite core
"yarn". As mentioned, the draft ratio of the composite core is
within the range of 1.05 to 1.16, preferably in the range of 1.10
to 1.14 and most preferably from 1.12 to 1.14.
[0062] The above draft ratio is calculated as the ratio of the
speed of rollers 14 vs. the speed of rollers 11, where the speed is
the angular speed on the surface of the rollers.
[0063] It should be noticed that also pre-tensioning bars 10,
contribute to obtaining the required draft ratio. The additional
pretension bars 10 are useful in increasing the draft ratio from
1.05 to 1.14 because they provide an alignment and slight tension
of the composite yarn 2, thus helping in the further stretch step.
This results in the extreme accuracy with which the composite core
"yarn" 2 is kept in the center of the final yarn 1.
[0064] Use of additional guide 15 and its staggered position with
respect of guide 16 also allow to feed the cotton roving always at
the same position and to prevent the moving of cotton roving during
the long run production. The combination of a better control in
keeping the position of cotton roving 8 and a high tension on
composite yarn 2 makes it possible to keep core 2 always in the
center of the final yarn 1 and to perfectly cover the core with the
staple fibers 3.
[0065] The two portions of final yarn 1 leaving draft rollers 14
are fed through guide 17 and spun together at spinning device 18,
known per se in the art and comprising in one embodiment ring,
traveler and spindle.
[0066] Any spinning method to produce a yarn 1 having a core 2
centered in a sheath 3 is within the scope of the present
invention. Such methods include e.g. covered yarn system (using
machinery by JCBT, Menegato, OMM, RATTI, RPR, Jschikawa) or
twisting machines (using machinery by Hamel, 2for1 by Volkman,
SiroSpin by COGNETEX or Zinser).
[0067] The elastic yarn produced as big weft packages as above
described with reference to FIGS. 2 and 3 can be used in production
of elastic denim fabric and garments, especially as weft yarn.
Machinery and methods of producing denim are well known in the art,
as an example, Morrison Textile Machinery or Sulzer Machinery or
modifications thereof maybe used to produce a denim fabric with
great elasticity and excellent stretch recovery.
[0068] The obtained fabric is then treated with finishing
processes, e.g. additional processes can be carried out such as a
thermal treatment of the stretched fabric to set the required
stretch value for the fabric itself. These treatment are known in
art and are carried out in function of the final characteristics
required for the fabric.
[0069] The invention will now be further disclosed with reference
to the enclosed non limiting examples.
Example 1
[0070] Yarn Count Test
[0071] ZWEIGLE L 232 (Zweigle, Germany)
[0072] 120 yards of yarn is wound to hank form using a Zweigle
device. The hank was weighted using a Metier PM600 (Metier,
Switzerland) weight scale. The yarn count was calculated using dtex
count system chart. This test was repeated 5 times for consistency
and accuracy.
Example 2
[0073] Yarn Evenness Test
[0074] USTER TESTER-4 (Uster, Switzerland)
[0075] Yarn package was set on the creel of the Uster tester-4.
[0076] The following parameters were set: [0077] Yarn name was
entered [0078] "Yarn" was selected as the setting for material
class [0079] Yarn count was entered [0080] "Uster statistic section
can not be accepted" has been selected [0081] "Cotton" was entered
as the setting for Raw material [0082] The value of Fibre micronare
was entered
[0083] UT 4-S section, Numbers of packages was set as "5"; number
of tests was set as "1"; test speed was set as "400 m/min"; testing
time was set as "0.5"; measurement slot was set as "automatic";
sucker was set as "60%"; test mode was set as "normal"; diagram
resolution was set as "standard"
Example 3
[0084] Strength, Elasticity and Breaking Force Measurement
[0085] USTER TENSORAPID-3 DEVICE (Uster, Switzerland).
[0086] Yarn was placed on the creel of the Uster tensorapid-3
device.
[0087] Yarn was passed through the spring guide.
[0088] The parameters entered in the program were: [0089]
"Synthetic yarn" option was selected [0090] Measured yarn count
(Example 1) was entered as Dtex yarn count system [0091] Number of
the test was set to "50" [0092] Testing speed was adjusted to "2000
m/min" [0093] Clamp pressure was set to "30%" [0094] Suct-off
pressure in the device was set to "50%" [0095] Blowing jets was set
to "off" position [0096] Yarn change was set to "IX" position
[0097] Yarn tensioner was set to "out" position [0098] Type of
measure was set to "test automatic" position
Example 4
[0099] Corespun Cotton+T-400
[0100] 150 Denier T-400 (Invista) as core yarn and cotton as sheath
was Core Spun in yarn mill Rieter Type G30 (Rieter, Germany)
equipped with Amsler core spinning device (STG4000. Amsler,
Switzerland). T-400 yarns were rewinded from big cylindrical cheese
packages to smaller cheese packages. The T-400 yarn was directly
fed to the center of the cotton drafting area. Draft ratio was set
to "1.1" The English Yarn count (hereinafter "Ne") 10/1 yarn was
spun. The yarn twist was set to "TM 4.2". The yarn spools were
wound in Savio Orion packaging machine as a weft packages.
[0101] See Table 1 for the result of measured strength, elasticity
and breaking force; yarn count test; and yarn evenness test as
described in EXAMPLES 1, 2, 3.
Example 5
[0102] Corespun Cotton+ELASTANE
[0103] 70 Denier ELASTANE (Lycra, Invista) as core yarn and cotton
as sheath was Core Spun in yarn mill Rieter Type 30 (Rieter,
Germany) equipped with core spinning device. ELASTANE is supplied
in packages that can be loaded directly to corespinning frames.
[0104] Draft ratio was set to "3.67"; Ne "12/1" yarn was spun; the
yarn twist was set to TM "4.5"; the yarn spools were wound in Savio
Orion packaging machine as a weft packages.
[0105] See Table 1 for the result of measured strength, elasticity
and breaking force; yarn count test; and yarn evenness test as
described in EXAMPLES 1, 2, 3
Example 6
[0106] T-400+ELASTANE
[0107] Preparation of the Core Yarn:
[0108] 70 Denier T-400 Invista yarn was intermingled with 40 Denier
ELASTANE yarn using a intermingling machinery (Sincro Jet, Fadis,
Italy).
[0109] Counting the number of the intermingling points: 1 meter of
yarn was placed on a black cloth; the intermingled points were
counted by eye. The test was repeated 5 times and average number
was defined as the intermingled points per meter.
[0110] The draft ratio of ELASTANE was set to "3.5"
[0111] Average 110 intermingling points were used in every 1
meter.
[0112] The core yarn (T400+ELASTANE composite yarn) is wound to a
package that can be loaded on the creel in the back side of the
ring spinning frame
[0113] The new yarn count was 77 Denier.
Example 7
[0114] Cotton+T-400+ELASTANE
[0115] Production of the core spinning cotton yarn with the core
yarn T-400+ELASTANE is as described in EXAMPLES 4 and 5. The new
composite
[0116] T-400+ELASTANE yarn was fed into core of the cotton
yarn.
[0117] Draft ratio was set to "1.14"; Ne "12/1" yarn was spun; the
yarn twist was set to TM "4.5" (.alpha.);
[0118] The yarn spools were wound in Savio Orion packaging machine
as a weft packages.
[0119] See Table 1 for the result of measured strength, elasticity
and breaking force; yarn count test; and yarn evenness test as
described in EXAMPLES 1, 2, 3. From Table 1 it is apparent that, as
far as elasticity is concerned, the invention yarn according to
example 7 is comparable with the cotton/elasthane-only yarn and is
better than the cotton/T400-only yarn; other parameters such as
resistance (RKM), break force, tick places etc. of the three yarns
are comparable.
Example 8
[0120] Weft Stretch Fabrics from cotton+T400
[0121] Weft Stretch Denim was prepared using corespun cotton+T400
yarn prepared as
[0122] described in EXAMPLE 4; Weaving specification: [0123] Warp
Yarn: Ne 7.4/1 Ring slub yarn dyed with indigo [0124] Warp Density
in reed: 21 [0125] Reed Width: 194 cm [0126] Weaving Loom: Sulzer
Double width Projectile [0127] Weft Yarn: Ne 10/1 Corespun
cotton+T400 (EXAMPLE 4) [0128] Weft Density: 20 [0129] Weave: 3/1
RHT [0130] Finishing: Singeing, hot washing with caustic soda
(reduce the fabric with), Padding in finishing pad (lubricant,
sewing agent and hand builder), [0131] and Sanforizing
Example 9
[0132] Weft Stretch Fabrics from Cotton+ELASTANE
[0133] Weft Stretch Denim was prepared using corespun
cotton+ELASTANE yarn prepared as described in EXAMPLE 2; weaving
specification: [0134] Warp Yarn: Ne 9/1 Ring Slub yarn dyed with
indigo [0135] Warp Density in reed: 24.4 [0136] Reed Width: 194 cm
[0137] Weaving Loom: Sulzer Double width Projectile [0138] Weft
Yarn: Ne 12/1 Corespun cotton-ELASTANE (EXAMPLE 5) [0139] Weft
Density (Finished fabric): 19.5 [0140] Weave: 3/1 RHT [0141]
Finishing: Singeing, hat washing (reduce the fabric with), Padding
in finishing pad (lubricant, sewing agent and hand builder),
Thermofixation in stenter frame (190 C in 43 seconds in width 158
cm), Sanforizing
Example 10
[0142] Weft Stretch Fabrics from Cotton+T-400+ELASTANE
[0143] Weft stretch Denim was prepared using corespun
cotton+T-400+ELASTANE yarn
[0144] prepared as described in EXAMPLE 3; Weaving specification:
[0145] Warp Yarn: Ne 9/1 Ring slub yarn dyed with indigo [0146]
Warp Density in reed: 24.4 [0147] Reed Width: 194 cm [0148] Weaving
Loom: Sulzer Double width Projectile [0149] Weft Yarn: Ne 12/1
Corespun cotton+T400+Lycra (EXAMPLE 7) [0150] Weft Density: 19.5
[0151] Weave: 3/1 RHT [0152] Finishing: Singeing, hot washing
(reduce the fabric with), Padding in finishing pad (lubricant,
sewing agent and hand builder), Thermofixation in stenter frame
(185 C in 30 seconds in 158 cm width), Sanforizing
Example 11
[0153] Testing
[0154] Denim fabric test samples were prepared from fabrics
produced in EXAMPLES 8, 9, and 10. Stretch and Recovery Tests were
conducted according to ASTM D3107.
[0155] Sample Preparation
[0156] Fabrics were washed in Wascator (Electrolux, Sweden) washing
machine according to BS 6330 2A at 60 C and subsequently dried in
Miele hometype dryer (Miele, Germany). This wash and dry process
were repeated 3 times. After the third drying, the fabrics were
conditioned (4 hours in conditioned lab 65% humidity, 20.+-.2
C..degree. hereinafter "conditioned"). After conditioning these
fabrics were cut and prepared for stretch and recovery tests. Three
rectangular section 60 mm.times.455 mm (wherein 455 mm was the
direction of stretch, hereafter "stretch side") of each fabric was
cut. The 60 mm side of each sample was raveled to exactly 50.5 mm.
Each sample was folded 32 mm from one end a seam was stitched 25 mm
from the fold. A 10 mm slit in the center of the strip on the fold
was created. The sample was left for 30 minutes on a flat surface.
A mark at center of the sample (250 mm) was made with a ruler.
[0157] Testing Procedures
[0158] The end of the sample in the top clamp of the stretch
testing instrument was clamped so that the looped end hangs free.
The marking distance was measured and recorded "A".
[0159] A dowel pin was inserted through the loop. A 1360 gr weight
was hooked through the slit. The sample was slowly pre-stressed by
cycling 3 times from zero to full load back to zero load taking
about 5 seconds per cycle and making sure the load stays down for
three seconds. After the third cycle the load was applied and the
sample was extended for 30 minutes. After 30 minutes the distance
between the benchmarks with the weight on the dowel was measured
"B". After measurement the weight was released and the sample
unclamped from the board and laid flat on the table. The sample was
relaxed for 60 minutes and the distance between the benchmarks was
measured "C".
[0160] Calculation
[0161] Fabric stretch was calculated according to following
formula:
% stretch=100.times.(B-A)/A
[0162] Fabric growth was measured at different time intervals
according to the following formula:
% growth=100.times.(C-A)/A
[0163] Table 2 test results show that the stretch of the invention
fabric is comparable with the stretch of the more elastic fabric
containing the cotton/elasthane only yarn. The stretch of the
fabric obtained from the T400-based yarn is comparable with the
stretch of a standard "natural" fabric, i.e. a fabric free of
stretch yarns, that is typically about 10%.
[0164] The growth of the invention fabric (3.1) is less than half
the value of the growth of the traditional fabric (7.8), thus
confirming the excellent results obtainable from the invention
yarn.
TABLE-US-00001 TABLE 1 yarn % % % uniformity THIN TICK TICK count
spinning strengh RKM % % ELN of % % % B-Force B-Force B-Force (NE)
method of yarn cv ELN. cv the yarn 40 35 50 HAIRNESS MIN. MAX. AVG.
12 C.PUN T400 + LYCRA 15.5 5.8 9.8 6.3 9.3 5 297 26 9.2 660 833 750
12 CORESPUN LYCRA 16.8 6.1 9.1 6.1 9.8 20 370 36 7.7 694 920 810 10
CORE-SPUN T400 14.1 8.0 7.7 6.1 8.6 1 199 12 9.9 700 978 815
TABLE-US-00002 TABLE 2 dimensional stability in washing weight
width Weft Spinning fabric (BS 6330 2A, 3 cycle) g/m.sup.2 cm
example Ne method FNISH welt (%) warp (%) unwashed washed unwashed
washed 15170 12 NEW denim -5.0 -3.5 356.0 380.0 153.0 145.6 YARN
fnish (core spun T400 + Lycra) 93821 12 CORE denim -8.5 -6.5 340.0
377.0 157.0 148.0 SPUN fnish LYCRA 3790 10 CORE denim -3.5 -4.0
399.0 421.0 146.5 141.5 SPUN fnish T400 stretch trowth- elongation
tear strenght Tensile strenght ASTM ASTM ASTM ASTM 1424 ASTM 5034
D3107 D3107 3107 weft warp weft warp weft weft example % (gr) (gr)
(kgf) (kgf) (%) (%) 15170 10.8 4279 7031 49.44 105.6 17.2 3.1 93821
11.2 4420 6784 45 100 18.7 7.8 3790 8.4 6303 7753 58.3 108 11.4
1.6
* * * * *